Table 2.
Summary of all potential risk factors included in the different analyses
| Independent variable | Recording method | Description | Breakdown category model | |
|---|---|---|---|---|
| Milking procedures | Hygiene during milking | Visual | 6-point scalea | High (0–2) vs. middle or low (3–5) |
| Udder and teats cleanliness | Visual | 4-point scaleb | High (clean) vs. middle or low (dirty) | |
| Tail cleanliness | Visual | 4-point scalec | High (1 and 2) vs. middle or low (3 and 4) | |
| Glove use | Interview | Whether or not gloves were used | Yes vs. no | |
| Pre-dipping | Interview | Whether or not the teats where dipped prior to milking | Yes vs. no | |
| Teats and udder drying | Interview | Whether or not the teats and udder where dried | Yes vs. no | |
| Elimination of first jets of milk | Interview | Whether or not the first jets of milk were eliminated | Yes vs. no | |
| Teat cups hygiene | Interview | Whether or not there was disinfection of teat cups between cows | Yes vs. no | |
| Post-dipping | Interview | Whether or not teats were dipped post milking | Yes vs. no | |
| Milking mastitic cows at the end | Interview | Milk mastitic cows last | Yes vs. no | |
| Milking machine management | Mobile milking machine | Interview | Use of a mobile milking machine | Yes vs. no |
| Hot water use | Interview | Use of hot water during milk routine | Yes vs. no | |
| Milk bulk tank | Interview | Refrigerated or mobiled | Refrigerated vs. mobile | |
| Mastitis diagnosis and treatment | Official milk control implementation | DHI | Existence of official milk control | Yes vs. no |
| CMT use | Interview | Use of CMT | Yes vs. no | |
| AST before treatment | Interview | Use of AST before treatment | Yes vs. no | |
| Veterinary assistance | Interview | Existence of veterinary assistance for mastitis treatment | Yes vs. no | |
| Treatment records | Interview | Existence of treatment records | Yes vs. no | |
| Dry cow period | Abrupt cessation of milking at dry-off | Interview | Use of abrupt cessation of milking | Abrupt vs. gradual |
| Dry cow therapy of all cows | Interview | Dry cow therapy of all cows | Yes vs. no | |
| Dry cow therapy according AST | Interview | Use of dry cow therapy according to AST | Yes vs. no | |
| Sealant use | Interview | Use of teat sealant | Yes vs. no | |
| Dry cows groups | Interview | Existence of dry cow group | Yes vs. no | |
| Calves | Calf suck its dam | Interview | Calf sucks it dam | Yes vs. no |
| Colostrum administration | Interview | Administration of colostrum | Yes vs. no | |
| For herd reposition | Interview | Calves for herd reposition | Yes vs. no | |
aAccording to Fregonesi and Leaver (2001): score 0—rear legs and tail, belly, clean udder; score 1—rear legs or tail with only minimal dirtiness, belly, clean udder; score 2—rear legs or tail with some dirtiness, belly, udder with minimal dirtiness; score 3—rear legs or tail dirty, belly, udder with some dirtiness; score 4—rear legs or tail very dirty, belly, udder dirty; score 5—rear legs or tail very dirty, belly, udder very dirty
bAccording to Schreiner and Ruegg (2003): clean—scores 1 (free of dirty) and 2 (slightly dirty, 2–10 % of surface area); dirty—scores 3 (moderately covered with dirt, 10–30 % of surface area) and 4 (moderately covered with caked dirt >30 % of surface area)
cAdapted to tail from Cook (2002): score 1—no manure present; score 2—minor splashing of manure; score 3—distinct plaques of manure; score 4—confluent plaques of manure encrusted
dMobile tank: non-refrigerated milk bulk tank. In five farms, both refrigerated and non-refrigerated milk bulk tanks were used
DHI dairy herd improvement, CMT California mastitis test, AST antibiotic sensibility test